The cause of anorexia nervosa is not known. Anorexia usually begins as innocent dieting behavior, but progresses to unhealthy weight loss. Social attitudes toward body appearance, family influences, and developmental factors are considered possible contributors to the cause of anorexia.
Teens with the disorder come from families that are challenged by appropriate problem solving, being too rigid, overly critical, intrusive, and overprotective.
Teens may also be immature in their emotional development, and are likely to isolate themselves from others..